1. Field of the Invention
This invention relates to semiconductor packages, and, more specifically, to a semiconductor package using a printed circuit board (PCB) and a method of manufacturing the aforementioned.
2. Description of the Related Art
Recently, semiconductor packages have started to use a PCB (Printed Circuit Board) instead of a conventional lead frame. The benefits of using a PCB include: lowering an inductance thereof, sharply improving the electrical capacity, providing a heat discharging capacity and providing a surface mounting capacity thereof.
The PCB used in the semiconductor packages includes a conventional thermosetting resin layer, a plurality of copper patterns at the top and bottom surfaces thereof, and a protective layer coated on the surfaces of the copper patterns.
Accordingly, there is a height difference between the existing portion and the nonexisting portion of the copper patterns. Also, the surface of the protective layer covering the copper patterns has a height difference. This height difference or the small winding makes the protective layer crack, owing to the pressure applied to the surfaces of the PCB during injection molding of an encapsulant for the plastic package. In a severe case, there is a chance that the electrically conductive patterns located on the inside of the protective layer can be cut.
Also, in a general sense, the protective layers are printed on the surfaces of the copper patterns several times during the printing process of the protective layer so that it makes the entire thickness of the PCB meet the standards. However, at this time, the rate of a bad semiconductor package that is due to a change of process condition such a mold gap, according to the change of process condition in the printing process of the protective layer, is increased.
Moreover, the protective layers are printed on the surfaces of the copper patterns several times, so that its thickness increases. Therefore, an air void between the copper patterns can easily occur during the printing process of the protective layer and in the following process, the air void also, is expanded, thereby lowering the reliance of the PCB.
Therefore a need existed to provide a semiconductor package and a method of producing a semiconductor package that overcomes the above problems.